Turbochargers are well known devices for supplying air to the intake of an Internal combustion engine at pressures above atmospheric pressure (boost pressures). A conventional turbocharger essentially comprises an exhaust gas driven turbine wheel mounted on a rotatable shaft within a turbine housing connected downstream of an engine outlet manifold. Rotation of the turbine wheel rotates a compressor wheel mounted on the other end of the shaft within a compressor housing. The compressor wheel delivers compressed air to the engine intake manifold.
One known approach to improving turbocharging efficiency and reducing emissions for an engine with a wide speed/load range is to provide a sequential two stage turbocharging system, comprising one relatively small high pressure turbocharger and another relatively large low pressure turbocharger. The turbochargers are arranged in series so that exhaust from the engine flows first through the smaller turbine of the high pressure turbocharger and then through the larger turbine of the low pressure turbocharger. The compressors of the two turbochargers are also arranged in series, with air flowing first through the relatively large compressor of the low pressure turbocharger and then through the relatively small compressor of the high pressure turbocharger.
For vehicle applications, the high pressure turbocharger and low pressure turbocharger along with the associated intercoolers and aftercoolers are mounted on the engine. However, this arrangement can be prohibitive in regard to cost, complexity and serviceability due to the complex plumbing and mounting arrangements required to support the air handling components on-engine. For stationary applications such as generators, the high pressure turbocharger and low pressure turbocharger along with the associated intercoolers and aftercoolers are mounted away from the engine to take advantage of engine serviceability that can be provided with such an arrangement. However, heretofore arrangements have not been provided that allow the same base engine configuration to be incorporated in stationary and mobile applications for both multi-stage turbochargers and single stage turbochargers without significant modifications to the engine configuration to accommodate the turbochargers. Therefore, there remains room for further improvements in this technology area.